I recently attended a two-day GT in Winchester. I took my World Eaters, who have been on a good roll recently at local RTTs, and wanted to see how they would fare at a larger event.
My list consisted of:
Angron
Lord Invocatus
Master of Executions- Berserker Glaive
Chaos Lord on Juggernaught- Favoured of Khorne
10 Berzerkers- 3 Plasma Pistols, Icon
Rhino
10 Jakhals
10 Jakhals
2 Chaos Spawn
6 Exalted Eightbound
3 Exalted Eightbound
3 Eightbound
Forgefiend- 2 Hades Autocannons, Ectoplasma Cannon
This is a list I have been trying out recently with the Forgefiend. I like the volume of autocannon shots, as they are great for clearing screens or marine bodies that I would need to trade a unit with in combat. The plasma cannon is also great for chipping away at vehicles or tougher bodies.
The Lord on Juggernaught is there for the blessing re-roll, as well as being a trade piece for actions or clearing units off of objectives.